Wiring question -

[hellatone]

I need some help on a wiring issue -- say I've got a 16-ohm head driving a 16-ohm speaker. I want to add a second speaker. I think I have two options -- one, I can get two new 8-ohm speakers and wire them in series; or two, I can get another 16-ohm speaker, and wire them in parallel. Is that right? And is there any difference in sound between series wiring and parallel wiring? Thanks! :smokin:

 

[SlyFoxx]

Re: Wiring question -

Two 8 ohm speakers in series will give you 16 ohms. You just add the ohms up to get the total.

Two 16 ohm speakers in parallel will give you 8 ohms. The proper formula is a bit more complicated but since 99% of the time folks wire up speakers with the same impedance you can divide the impedance (in this case 16) by the number of speakers. (in this case 2) ..so 16/2 = 8

Rule of thumb...adding in series increases impedance....adding in parallel decreases impedance

As for sound difference...it would be negligible.

 

[hellatone]

Re: Wiring question -

Two 8 ohm speakers in series will give you 16 ohms. You just add the ohms up to get the total.

Two 16 ohm speakers in parallel will give you 8 ohms. The proper formula is a bit more complicated but since 99% of the time folks wire up speakers with the same impedance you can divide the impedance (in this case 16) by the number of speakers. (in this case 2) ..so 16/2 = 8

Rule of thumb...adding in series increases impedance....adding in parallel decreases impedance

As for sound difference...it would be negligible.

thanks -- i didn't know you could wire speakers of different impedance -- how does the formula go for that?

 

[Soujurn]

Re: Wiring question -

The total impedance of a circuit is the square root of the sum of the squares of the resistance and reactance.

But disregarding reactance you can use this formula.

1/ (1/R1 + 1/R2 + etc....) Up to the number of R's (speaker resistances) you have.

Lets say you have a 8 ohm speaker and a 16 ohm speaker.
In parallel, this would be 1/((1/8) + (1/16)), or... 5.3 ohms.

 

[muttonchopsrule]

Re: Wiring question -

thanks -- i didn't know you could wire speakers of different impedance -- how does the formula go for that?

i wouldn't recommend wiring together speakers of a different impedence. it can be done, but the problem is (as Soujurn pointed out), that's when you'll end up with some goofy total impedence that won't match your amplifier's impedence.

 

[hellatone]

Re: Wiring question -

so let me get this straight -- this means that i can't get a second 16-ohm speaker to use with the one i already have with a 16-ohm head, because then i'll have an 8-ohm set-up which won't work with my 16-ohm head? so if i want a second speaker, i have to buy two new ones at 8-ohms each? To what extent, if any, can tube amps safely drive speakers that don't match the amp's impedence? wow that's a lot of questions..... :smokin:

 

[Sludgenutz]

Re: Wiring question -

so let me get this straight -- this means that i can't get a second 16-ohm speaker to use with the one i already have with a 16-ohm head, because then i'll have an 8-ohm set-up which won't work with my 16-ohm head? so if i want a second speaker, i have to buy two new ones at 8-ohms each?

Yes! Or you could buy 3 more 16 ohm speakers for a total of 4 or 16 ohms depending on the way they are wired!

To what extent, if any, can tube amps safely drive speakers that don't match the amp's impedence? wow that's a lot of questions..... :smokin:

It is generally not recommended to mismatch the output impedeance of the amp and speakers. There is some natural leeway, as the actual impedence varies constantly and dynamically any time you play through the amp. Large "permanent" mismatches should be viewed with suspicion.

 

[LooseCannon]

Re: Wiring question -

If you have a 100 watt amp you could pull out the two inner tubes and use it with an 8 ohm cab.

 

[Robert Delahunt]

Re: Wiring question -

I need some help on a wiring issue -- say I've got a 16-ohm head driving a 16-ohm speaker. I want to add a second speaker. I think I have two options -- one, I can get two new 8-ohm speakers and wire them in series; or two, I can get another 16-ohm speaker, and wire them in parallel. Is that right? And is there any difference in sound between series wiring and parallel wiring? Thanks! :smokin:

If it's two 16 ohm in parallel, they half, therefore it would be 8 ohms. I'd say how many speakers do you want? You could run four 16 ohm if you wired them correctly, but just 16 ohm, I don't think you could actually run them in a way where two of them = 16 ohm without an impedance matcher.

 

[Scott_F]

Re: Wiring question -

Does your amp not have a way to select output impedance?